This application addresses a common condition resulting in head deformation in infants. Deformational occipital flattening, known as plagiocephaly (Greek: “oblique head”) for asymmetric forms and brachycephaly (Greek: “short head”) is the most common type of abnormal head shape. Plagiocephaly is believed to be caused by prolonged or repetitive external force (e.g., gravitational weight of the head or brain) applied to an infant's head. For example, with an infant habitually placed on its back to sleep, the weight of the infant's head, including the weight of the brain and other tissue within the head, provides a downward force on the posterior portion of the infant's skull. Anterior-posterior strain on the cranium can cause or exaggerate this effect. Since the skulls of infants are growing, an infant habitually laid on its back can develop a deformation of the skull which in some cases is observed as an excessive flattening of the head. The result of plagiocephaly is an apparent, unsightly, and perhaps harmful shape deformation of the skull, which in some cases affects the appearance of the child's face and can be permanent if not addressed and treated early on. Plagiocephaly, or asymmetrical flattening, is quantified using oblique cranial measurements, of transcranial difference. Landmarks for these points vary, but the average normal difference is 3-4 mm. Brachycephaly, or symmetrical flattening, is quantified using cephalic index (“ci”) representing the ratio of the width and the length of the head. The width of the head can be measured as the distance between the right and left euryon (“eur” and “eul” respectively), while the length of the head can be measured as the distance between the glabella (“gb”) to the opisthocranion point (“op”). The cephalic index (“ci”) is thereforeci=(((eur−eul)*100)/(gb−op))                and is considered abnormal if it is two standard deviations above or below the mean values. Cephalic index values for infants up to 12 months old have been measured and typically range between 80-85.        
Plagiocephaly is a type of calvarial deformity that has been recognized since antiquity, but the incidence of clinically-significant plagiocephaly and brachycephaly has increased in Western societies following the 1992 American Academy of Pediatrics (“AAP”) recommendations for supine infant positioning (“Back to Sleep Campaign”). This campaign appears to have contributed to decreasing the incidence of sudden infant death syndrome (SIDS), but has resulted in a rise in the number of infants with occipital flattening. Some reports estimate rates of occipital flattening in young children to be as high as 20% at 2 years of age.
More technically speaking, the occipital deformational processes are believe to be a result of regional calvarial growth restriction from sustained contact with a flat resting surface. In most cases, the affected infants have poor head rotation related to tight cervical muscles (torticollis) which are a result of limited head movement in-utero. The neck muscle contracture persists after birth, so the infant's head position can assume a similar position to that held prior to delivery, and the infant's neck muscles may not be sufficiently developed to cause proper head movement after birth. Supine positioning, as recommended by the AAP, places the expanding occiput against a typically flat resting surface. The downward (gravitational) force acting on the infant's head is resisted by an equal and opposite force from the resting surface (pillow or mattress).
FIG. 1, adapted from the public domain, illustrates a normal profile (A) of a child's head and a distorted profile (B) of a child's head suffering from positional plagiocephaly. The distorted profile (B) shows how flat spots, angular effects, and relative misalignment of one ear relative to the other is possible. A general shape of the head in both profiles is indicated by the dashed lines, with the external gravitational force being indicated by the arrow and the letter “g” above.
With infants experiencing cervical tightness, these infants may not be able to reposition their heads sufficiently to redistribute the forces opposing calvarial expansion. Hence, the head resting surface will continue to resist calvarial expansion until the infant has sufficient strength and motor development to overcome the neck contracture (usually at 3-4 months). The degree of neck muscle contracture and the rate of neuromuscular development, both of which vary considerably in new-born infants, can determine how long this process persists and, therefore, determine the severity of the head flattening. For this reason, conditions that cause more prenatal head restriction (e.g. oligohydramnious, multiple births, large infants, etc.) may be more likely to cause occipital flattening. Also, conditions that protract neuromuscular maturity (e.g. prematurity or developmental delays) may lead to a longer period of occipital growth restriction and greater head flattening.
One present attempted solution to treat plagiocephaly is a special molding helmet onto the affected child's head in an attempt to correct the condition. This approach is an active reshaping approach, and its results are not favorable if the condition has developed beyond a certain stage. This solution is not ideal as it is unsightly and uncomfortable for the child and its family. In addition, this solution does not prevent the condition before its occurrence, and does not address the concurrent problem of torticollis.
Other attempts to treat plagiocephaly include placing a child on an angled cushion that causes the child to rest at an angle out-of-plane with the child's mattress (and in other words not normal to the direction of gravity's pull). This solution is not ideal because it is uncomfortable for the child and requires the child's parent to constantly get up and move the child or adjust the cushion on which the child is resting, which in turn disturbs the sleep of both the child and the parent.
Other (non-helmet) solutions to treat plagiocephaly include orthotic devices that can be classified into two general classes: resting surface alterations, and repositioning devices. Resting surface modifications attempt to increase the contact surface area between an infant's head and the head resting surface. Typical resting surface modifications include: memory foam, contoured pillows, cut-out surfaces, and slings. Each of these solutions has design characteristics that limit their usefulness.
Repositioning devices attempt to vary the point of contact between the surface and the infant's occiput (e.g., wedge-shaped cushions). These repositioning devices offer little if any benefit to infants with established plagiocephaly, and have not been demonstrated to prevent plagiocephaly. For example, wedges do not address the limited neck motion (torticollis) in infants. Also, even with consistent use, the at-risk infant will still lay with its head rotated to one side and positioned against a flat surface, and relies on constant and proper adjustment by the infant and the device by the infant's parent. Continuous adjustment of the infant or the device is tiring and difficult for most parents, who are reluctant to continually wake their sleeping infant and get up themselves during the night. Furthermore, wedges ate relatively ineffective after about 4 months of age because of increased mobility of the child. Most infants are able to roll over at 5 months and can roll off of these orthotic devices.
In summary, the present attempted solutions to treat plagiocephaly are not effective, and requite active and proper administration by the child's parent, which the parent may not perform properly causing other or further harm, or which the parent may not be willing or able to do, or which the parent may neglect or forget to do. These attempts also do not effectively address the neck motion (torticollis) problems of infants that place them at risk of plagiocephaly in the first place.